New species of trapdoor spiders already in decline

11 May 2018

A group of south-western Australian trapdoor spiders have been listed as threatened species, despite only just being formally named.

A research group led by Queensland Museum scientist Dr Michael Rix, along with colleagues at the Western Australian Museum, University of Adelaide and South Australian Museum, has not only described the 15 new species of trapdoor spiders, but also highlighted the conservation challenges facing this group.

The paper published in ZooKeys is a large revision of new species of trapdoor spiders in the genus Idiosoma, which Dr Rix says have such great conservation significance.

“They are the face of invertebrate conservation in some parts of Western Australia,” Dr Rix said.

“The group includes the only spider in Australia that is on both the Western Australian state and the Commonwealth threatened species lists, and after our work, a further two species have been listed on the Western Australian threatened species list.”

Dr Rix said trapdoor spiders can provide a good indication of how natural landscapes are faring, and if a population is struggling to survive in an area, that can indicate a serious problem.

“Where trapdoor spiders exist in the landscape and exist in good numbers, it is a good indication that these habitats are doing relatively well compared to other places where trapdoor spiders no longer occur due to long term declines,” he said.

The research also highlighted that there can be real time declines and conservation challenges faced by animal species that are still not formally named.

“These are threatened species and they do exist in the landscape and some are declining seriously, yet in many cases we still don’t have scientific names for them,” Dr Rix said.
“It’s a particular problem for invertebrates such as spiders and insects and it’s crucial that we get a handle on the taxonomy and the names of those species before they are lost forever.”

Aside from the conservation significance of the new species of spiders, they are unique in that they are one of only a few groups of animals in the world that use their bodies as another layer of defence to protect their homes.

“These spiders have essentially turned the backs of their bodies into armoured shields, which they use to plug their burrows and defend themselves against predators,” Dr Rix said.

“They are one of only a few spiders in the world that have this defence mechanism.”

Queensland Museum Network Acting CEO Dr Jim Thompson said this scientific paper highlighted the important work that taxonomists do.

“For many people spiders are feared but they actually play a very important part in our eco-system and this research is significant in identifying at risk species,” Dr Thompson said.

“Queensland Museum scientists are world renowned and are fortunate to be able to collaborate with scientists from a variety of institutions across the globe to support valuable research.”